In this work, crossflow microfiltration performance of beers, characterised by different turbidity levels (at 20 °C) in the ranges of 2.4-52.4 EBC unit, was assessed in a bench-top plant, appropriately designed and equipped with a 0.8-μm ceramic tubular membrane module, under constant feed superficial velocity (vS = 6 m s-1), transmembrane pressure difference (TMP = 3.74 bar), temperature (∼10 °C), and periodic CO2 backflushing. The quasi steady-state flux (Jv,ss) was reached after about 1 h, independently of the turbidity (H) of rough beer. Its decline was drastic as H increased from 0 to 2-3 EBC unit and tended to an asymptotical value of 91 ± 8 dm3 m-2 h-1 for H > 7 EBC unit. By removing yeast cells and larger aggregates via centrifugation, or hydrolyzing firstly the gel forming polysaccharides and, secondly, get rid of the suspended solids by centrifugation, it was possible to increase Jv,ss to 137 ± 13 or 294 ± 30 dm3 m-2 h-1. Periodic CO2 backflushing of rough beer resulting from combined enzymatic and centrifugal pre-treatments was able to lower the overall hydraulic resistance to (5.2 - 8.1) x 1011 m-1, values near to the resistance of clean membrane.
Rough beer clarification by crossflow microfiltration in combination with enzymatic and/or centrifugal pretreatments
MARCONI, Ombretta;
2013
Abstract
In this work, crossflow microfiltration performance of beers, characterised by different turbidity levels (at 20 °C) in the ranges of 2.4-52.4 EBC unit, was assessed in a bench-top plant, appropriately designed and equipped with a 0.8-μm ceramic tubular membrane module, under constant feed superficial velocity (vS = 6 m s-1), transmembrane pressure difference (TMP = 3.74 bar), temperature (∼10 °C), and periodic CO2 backflushing. The quasi steady-state flux (Jv,ss) was reached after about 1 h, independently of the turbidity (H) of rough beer. Its decline was drastic as H increased from 0 to 2-3 EBC unit and tended to an asymptotical value of 91 ± 8 dm3 m-2 h-1 for H > 7 EBC unit. By removing yeast cells and larger aggregates via centrifugation, or hydrolyzing firstly the gel forming polysaccharides and, secondly, get rid of the suspended solids by centrifugation, it was possible to increase Jv,ss to 137 ± 13 or 294 ± 30 dm3 m-2 h-1. Periodic CO2 backflushing of rough beer resulting from combined enzymatic and centrifugal pre-treatments was able to lower the overall hydraulic resistance to (5.2 - 8.1) x 1011 m-1, values near to the resistance of clean membrane.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
